The use of valve assemblies to relieve pressure is well known in the art. For example, U.S. Pat. No. 1,124,203 to Bingley discloses a safety valve suitable for use in connection with the brake cylinder of an air brake apparatus that prevents excessive pressure in the brake cylinder such as might result in the locking of car wheels.
U.S. Pat. No. 1,891,119 to Stover discloses a safety valve designed to relieve pressure in a vessel, such as the cylinder of a compressor when excessive pressure accumulates therein.
U.S. Pat. No. 2,254,209 to Buttner discloses a pressure relief valve that prevents the accumulation of fluid under or behind a sealing member in a valve.
U.S. Pat. No. 2,297,378 to Wittenberg discloses a pressure control and indicator gauge for use in connection with pressure cookers.
U.S. Pat. No. 2,710,627 to Wagner, et al. discloses a pressure controlling cap structure which vents any excess pressure within a cooker vessel.
U.S. Pat. No. 3,189,040 to Johnson discloses a spring loaded pressure relief valve.
U.S. Pat. No. 3,651,827 to Hammer, et al. discloses a pressure relief valve that is connected on one side to a high pressure of a fluid or hydraulic or lubricating system and on the other side to a low pressure side.
U.S. Pat. No. 4,049,017 to Jones discloses a pressure relief valve having a sealing member which is capable of moving into and out of sealing engagement with a valve seat as the valve member slides in the passageway.
U.S. Pat. No. 4,140,148 to Richter discloses a sanitary pressure relief valve with drain ports.
U.S. Pat. No. 4,143,787 to Walker discloses an air vent pressure relief plug for use with pressure cookers.
U.S. Pat. No. 4,889,151 to Oten discloses a pressure relief valve having a valve member that smacks and permanently deforms a deformable over pressure indicating element to give a permanent indication of an over pressure situation.
U.S. Pat. No. 5,623,962 to Danzy, et al. discloses a pressure relief valve having an inlet port and an outlet.
U.S. Pat. No. 6,668,853 to Dean discloses a pressure relief valve for use in highly corrosive environments having parts exposed to corrosive lading which are relatively easily field-replaceable.
While the prior art discloses a myriad of pressure relief valves, various industries using tanks, pipes and other various forms of closed containers that move or store liquid and gas are continuously looking to improve existing valve assemblies and their design. Innovation for improved valve assemblies is partly a result of the desire for less complicated, less costly and more effective ways to relieve and detect too much pressure in a valve assembly.
Some industries, such as the food and beverage industry, sometimes require sanitary conditions in the transport or storage of semi-solid food or liquid beverages. As such, sanitary pressure valves that prevent the contamination of goods or items held or transported in a closed system while also relieving overpressure situations is an absolute necessity.
Therefore, it may also be desirable to have a pressure relief valve assembly that allows a user to adjust the pressure needed to activate the pressure relief feature of the valve. This feature is useful because a closed system such as a tank may be used to transport or store a variety of gases and liquids. Because different liquids and gases create varying pressure conditions in a closed system, it would be desirable to have a pressure relief valve assembly that is adjustable.
In some situations, a valve assembly may accumulate build-up or residue from gas or liquid that remain on its surface. To avoid such build-up or residue, it would be desirable and advantageous to have a valve assembly that allows easy access and cleaning of the interior chamber of a closed valve assembly. Further, it is desirable and advantageous to have a valve assembly that can be accessed, inspected and cleaned without having to remove valve assembly from the pressurized vessel or substrate, keeping the vessel or substrate in a pressurized state while examining the interior of the valve assembly.
In other situations, it may be necessary to know when a closed system has exceeded a certain pressure level. For example, in a closed system with pipes, an overpressure situation may indicate a blockage in the system. Therefore, it would be advantageous to have a valve assembly with a visual cue that alerts a user that a certain pressure has been exceeded in the system. Furthermore, it would be useful if the valve assembly allowed a user to reset the visual cue that indicated the overpressure situation in the first place. A visual cue that may be reset is desirable because a new valve assembly would not be needed to replace the existing valve assembly. Simply resetting the visual cue on the valve assembly would allow its continued use.
Pressure relief valves are required in many instances because, for example, beverages may be infused with gases such as CO2 or subjected to various temperature extremes. Gases and varying temperatures in a closed system cause pressure differentials. Without pressure relief valves, explosions and injuries to people around such closed systems would occur in the event the pressure level in a closed system exceeded the closed system's capacity.
Accordingly, there is a need for an adjustable sanitary valve assembly that relieves pressure and displays some visual cue that a certain pressure has been exceeded in a closed system. There is a also a need for a sanitary valve assembly that allows a user to manually adjust the pressure needed to activate the pressure relief mechanism of the valve assembly. Further, there is a need for a valve assembly that allows the user to access and inspect the interior of the assembly without removing and/or unsealing the valve from the vessel or substrate. Finally, there is a need for a low cost and effective sanitary valve assembly that can be efficiently cleaned and reused.